A long standing problem associated with rotary valves, such as in-line ball valves, is that flow-induced hydraulic forces developed when the valve is positioned in a partially opened position can cause the ball valve member to creep from the set position thereof and actually shut. While a twist lock handle can be used to secure the valve member in its set position, this type of lock is not suitable for applications where the valve is not accessible to the operator. Accordingly, there is a need for a locking device which can be used in all applications of a rotary valve.
One device that has been used involves the provision of a coil spring which is responsive to the flow-induced movement of the valve member to move to a locking position preventing movement of the valve member. The coil spring is moved to a non-locking position when the valve member is moved by a separate stem portion connected to a handle to permit the adjustment of the valve member to a desired flow controlling position. However, this prior art locking mechanism involves the use of an excessive number of complicated parts and is thus expensive. Also, the device is subjected to wear because of the high forces caused to operate between the coil spring and the valve stem.
Another problem associated with rotary valves which are to be used in remote inaccessible locations is that of making them adaptable to be adjusted by rods attached to the handle. To this end, it is desirable to have a handle which can be positioned to a plurality of different handle configurations.